Invasive Pressure Monitoring: General Principles

The sophistication of bedside intensive care unit (ICU) monitoring equipment and the precision of its displayed values may tempt clinicians to accept these data without question. However, critically ill patients place substantial demands on these measurement technologies. Although the technology is governed by rigorous industry standards, it is not foolproof. To ensure accuracy and recognize and correct sources of error, the practicing intensivist must be aware of key technical aspects of pressure transduction. This chapter reviews the basic principles of vascular pressure measurement, including principles of wave transmission, transduction, signal processing, and recording. Clinical aspects of measuring vascular pressure, such as its indications and interpretation of findings, are covered in other chapters. The goal of this chapter is to equip the practicing clinician to select the appropriate measurement tool, optimize its performance, and recognize and correct its shortcomings.